Until the {k} spirit shall be poured upon us from on high, and the wilderness shall be a fruitful field, and the {l} fruitful field shall be counted for a forest.

(k) That is, when the Church will be restored, thus the prophets after they have denounced God's judgments against the wicked, used to comfort the godly, lest they should faint.

(l) The field which is now fruitful, will be but as a barren forest in comparison to what it will be then as in Isa 29:17 which will be fulfilled in Christ's time, for then they who were before as the barren wilderness, being regenerate will be fruitful and they who had some beginning of godliness, will bring forth fruit in such abundance, that their former life will seem but as a wilderness where no fruit was.

Wesley's Notes

32:15 Until - Until the time come, in which God will pour, or, as the Hebrew word properly signifies, reveal, evidently and plentifully pour out his spirit from heaven upon his people, which was fully accomplished in the days of the Messiah. The fruitful field - God's people who were desolate, shall be revived and flourish, and their flourishing enemies shall be brought to destruction.

Jamieson-Fausset-Brown Bible Commentary

15. This can only partially apply to the spiritual revival in Hezekiah's time; its full accomplishment belongs to the Christian dispensation, first at Pentecost (Joe 2:28; Ac 2:17), perfectly in coming times (Ps 104:30; Eze 36:26; 39:29; Zec 12:10), when the Spirit shall be poured on Israel, and through it on the Gentiles (Mic 5:7).

wilderness . fruitful field . forest-when Judea, so long waste, shall be populous and fruitful, and the land of the enemies of God shall be desolate. Or, "the field, now fruitful, shall be but as a barren forest in comparison with what it shall be then" (Isa 29:17). The barren shall become fruitful by regeneration; those already regenerate shall bring forth fruits in such abundance that their former life shall seem but as a wilderness where no fruits were.

Matthew Henry's Concise Commentary

32:9-20 When there was so much provocation given to the holy God, bad times might be expected. Alas! how many careless ones there are, who support self-indulgence by shameful niggardliness! We deserve to be deprived of the supports of life, when we make them the food of lusts. Let such tremble and be troubled. Blessed times shall be brought in by the pouring out of the Spirit from on high; then, and not till then, there will be good times. The present state of the Jews shall continue until a more abundant pouring out of the Spirit from on high. Peace and quietness shall be found in the way and work of righteousness. True satisfaction is to be had only in true religion. And real holiness is real happiness now, and shall be perfect happiness, that is, perfect holiness for ever. The good seed of the word shall be sown in all places, and be watered by Divine grace; and laborious, patient labourers shall be sent forth into God's husbandry.